LOL. I haven't had a "butt" call, but I have had a "pocket" call.
Just a few months ago, my sister had put her cell phone in her pocket and she must have been leaning against the counter or something but my phone rings and it comes up as my sister and I thought "oh how cool shes calling me in the daytime" I rarely hear from her so I was a bit excited. Anyways, I can hear her talking to someone and alot of noise in the background, I kept saying "Hello Hello hello" and she wasnt answering me. So I would hang up the phone and wait a few minutes and she called me back and again the same thing. I could tell nothing was wrong because of what I was able to hear. So I called my mom and she called my sisters job just to tell her TO STOP CALLING me if she wasnt going to talk to me. LOL And thats how we found out it was her Pocket that kept calling me. lol